8389921 has 2 divisors, whose sum is σ = 8389922. Its totient is φ = 8389920.

The previous prime is 8389919. The next prime is 8389937. The reversal of 8389921 is 1299838.

8389921 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7349521 + 1040400 = 2711^2 + 1020^2 .

It is a cyclic number.

It is not a de Polignac number, because 8389921 - 2¹ = 8389919 is a prime.

It is a super-4 number, since 4×8389921⁴ (a number of 29 digits) contains 4444 as substring.

Together with 8389919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (8389951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4194960 + 4194961.

It is an arithmetic number, because the mean of its divisors is an integer number (4194961).

Almost surely, 2^8389921 is an apocalyptic number.

It is an amenable number.

8389921 is a deficient number, since it is larger than the sum of its proper divisors (1).

8389921 is an equidigital number, since it uses as much as digits as its factorization.

8389921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 40.

The square root of 8389921 is about 2896.5360346455. The cubic root of 8389921 is about 203.1979351811.

The spelling of 8389921 in words is "eight million, three hundred eighty-nine thousand, nine hundred twenty-one".